The International Olympic Committee will target Russia, Mexico and Kenya in pre-Olympic drugs testing due to the countries' track records as it looks to root out cheats ahead of this year's Rio de Janeiro Games.
"Special focus will be put on countries where the testing program is non-compliant - Kenya, Russia and Mexico," the IOC said in a statement.
The ruling body said it was also doubling the budget allocated for pre-Olympic drugs testing from $735 thousand to almost 41.5 million.
It will be targeting those sports the World Anti-Doping Agency considers most affected while extending the re-testing of medallists from the Beijing 2008 and London 2012 Olympics which has already netted more than 50 positive results.
Marina Savinova who won the 800m at the London Olympics is among those affected by the Russian doping scandal.
Russia has been at the heart of a huge doping scandal and the country's track and field athletes have been suspended pending an investigation.
More than 20 Russian athletes have also tested positive in re-tests of samples from Beijing and London, putting their participation in Rio with a full team in doubt.
Kenya and Mexico have failed to get their doping program in line with WADA's demands.
Kenya, a global powerhouse in middle and long-distance running, has been in the spotlight recently following allegations of widespread doping by its athletes.
"We want to make sure any targeted athletes who have a positive result will be stopped from competing in Rio," IOC spokesman Mark Adams said.
The IAAF, the world governing body of athletics, will decide on June 17 whether Moscow has done enough to clean up its act in order to be readmitted to competition, though calls to ban Russian athletes from the Rio Games are growing.